Children produce weaker coronavirus antibodies, findings

New studies suggest that children infected with the coronavirus produce weaker antibodies than adults, have fewer of them, and clear the infection much faster. Published on Thursday..

Other studies Overly strong immune response It may be blamed on someone who has become severely ill or died of Covid-19. A child’s weak immune response, paradoxically, may indicate that the virus defeats the virus before it causes havoc in the body, a severe coronavirus-induced disease, Covid. It can help explain why the child is mostly immune to the symptoms. It may also indicate why the virus is unlikely to spread to others.

“They may be infected for a shorter period of time,” said Donna Farber, an immunologist at Columbia University in New York, who led the study reported in the journal Nature Immunology.

Weak and low antibodies do not increase the risk of reinfection in children, according to other experts.

“You really don’t need a huge, overly strong immune response to maintain protection for a period of time,” said Deepta Bhattacharya, an immunologist at the University of Arizona at Tucson. “I don’t know if I’m particularly worried that my children’s antibody response may be a little low.”

This study looked at antibody levels in children at some point in time, but was too small to provide insight into how age-related levels change. However, it can question certain antibody tests that can cause an infected child to go missing.

Dr. Farber and her colleagues analyzed antibodies to the coronavirus in four groups of patients. 19 adult convalescent plasma donors who recovered from Covid without hospitalization. Thirteen adults hospitalized for acute respiratory distress syndrome due to severe Covid. 16 children hospitalized for multisystem inflammatory syndrome. It is a rare condition that affects infected children. 31 infected children who did not have the syndrome. About half of the children in this last group were completely asymptomatic.

Individuals in each group had antibodies. This is consistent with other studies showing the majority of people infected with the coronavirus. Initiate a strong immune response..

“This further emphasizes that the virus infection itself, and the immune response to the virus, is not much different than we would expect,” said Petter Brodin, an immunologist at the Karolinska Institute in Stockholm. “.

However, the range of antibodies was different between children and adults. Children primarily produced a type of antibody called IgG that recognizes spike proteins on the surface of the virus. In contrast, adults made several types of antibodies against spikes and other viral proteins, which were more potent in neutralizing the virus.

Dr. Farber said the children “have less protective response, but less widespread antibody response.” “That’s because those children aren’t so badly infected.”

Neither group of children had antibodies to a viral protein called nucleocapsid or N that was entwined with the genetic material of the virus. Because the protein is inside the virus rather than on the surface, the immune system recognizes it only when the virus is widespread in the body and makes antibodies, she said.

“Children don’t really see that, which suggests that if these children are infected, the course of the infection is really reduced.” She explained.

The results of this study can compromise the results of tests designed to be picked up. Antibodies to N protein Of the virus. Many antibody tests, Including those made by Abbott and Roche Provided by Quest Diagnostics and LabCorp and unique to N-antibodies, you may miss a child who has successfully cleared the virus. “That’s the absolutely interesting implication of that discovery,” said Dr. Brodin.

Low levels of the virus in the body also explain why children generally appear to be less infected with the virus than adults.

However, experts cautioned in interpreting the results, as the results represent samples taken from people at a particular point in time.

Samples from more severely affected children and adults were collected within 24-36 hours of hospitalization or intubation due to respiratory failure. Those from mild or asymptomatic children were deposited in the bank after medical treatment.

The type of antibody produced in the body depends on the time of infection. This was the limit of the study, Dr. Brodin said, as researchers may have compared people at different points of infection. “There is a risk of comparing apples and oranges.”

Other experts warned that the study was too small to draw conclusions about how the immune response of children of different ages would change. The children in this study ranged from 3 to 18 years with a median age of 11.However, in some studies, teenagers Just as dangerous From coronavirus as an adult.

Dr. Maria L. Gennaro, an immunologist at Rutgers University, said, “It is very important to understand what is happening to children,” not only the nature of their illness, but also the children’s community. It is also important to understand how it contributes to the spread of the virus in society. But “trying to stratify by age makes the analysis a bit more difficult,” she said.

Researchers have also been unable to explain why children’s antibody responses are more restricted.

Low levels of antibodies may seem bad, but “high levels of antibodies are not always a good marker,” said Dr. Bhattacharya. “This usually means that the problem occurred early in the response.”

At least one other study suggested that children have Strong innate immune systemAiming to fight the many new pathogens they encounter, this first line of defense can eliminate the infection early, without having to rely on later antibodies.

Another possibility is that children have some protection in the form of immune cells called memory T cells because they had previously encountered the common cold coronavirus.

“Is it all innate, or do you really have existing memories?” Dr. Batacharya said. “I think both are possible.”